How to seal the room - gaps between galvanized ducting pipes and drywall

Growroom Design
#1

Hi,
I have ducting in diameter of 355mm or 14 inch. I want to seal my room, so how to I close the air gaps where the ducting goes through my drywall?

I used galvanized metal sheet ducting parts to go through the drywall and then connected sonoduct hoses. Sometimes the gaps between the glavanized form parts are only smal, so I guess I just can use acrylic or silicone for that.

But some times the gaps are a bit bigger e.g. 1 inch. How do I seal that? I also have joint compund here, but I guess that is maybe to rigid and doesnt connect well to the galvanized metal sheet parts? Or should I use silicone with some filling materials extra?

Or how about that stuff: https://www.greatstuff.dupont.com/how-to-air-seal-hvac-ducts-and-penetrations.html

Is that good?

2 Likes
#2

The foam would work in the link. You could also just use reflective heating tape. Or even better…foam it …let foam dry, cut off excess foam and then cover with heating tape to make it look clean.

9 Likes
#3

If you’re handy with a caulking gun, a 1 inch gap is doable with silicon. If push comes to shove, you can fill the gap over a couple of episodes, just let the silicon dry before applying your next “layer”. Another option would be to use sikaflex or similar product. For a smooth finish, use soapy water in a spray bottle, spray your project, spray a little on your finger and smooth away.

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#4

How can I prevent that such a big silicone gap will develop tears? Or will it not develop that?

I was thinking first to use the foam for big gaps and the silicone for small ones, but it seems silicone and pu foam is not good to use together. Maybe I just use silicone because I think the foam is not ideal for the small gaps.

So probably the pu sealant is the thing to go.

Can you tell me how to use these plastic sausages, in what can I put them in? :smiley:
https://www.buildmate.com.sg/product/pu-sealant-sikaflex-construction-ap-sika/

#5

Look for foam backer rod. It comes in different diameters. Stuff that into the gap and then caulk or apply some sort of compound over it.

4 Likes
#6

You could stuff almost anything in there, old rags, insulation, foam, and then cover it all with foil tape as mentioned above. Spray foam would be good too, but it can be really messy.

3 Likes
#7

foam it wait for it to harden and shape or dont. They make a wide gap formulation.

3 Likes
#8

I did buy sikaflex and it was exactly what I was looking for. Thanks for that :wink:

2 Likes